Fluid pressure control mechanism



Oct. 29, 1935. FIG. FOLBERTH El AL 2,018,843

FLUID PRESSURE CONTROL MECHANISM Filed July 26) 1932 2 Sheets-Sheet l 3nventor a FEEDER CA 6- l'WZBE/PTH GttorueuS 1935' G; FOLBERTH El AL I 2,018,843

FLUID PRESSURE CONTROL MECHANISM Filed July 26, 1952 2 Sheets-Sheet 2 By- M Patented Oct. 29, 1935 PATENT OFFICE FLUID rnnssunu con-moi. iuucuamsm Frederick G. Folberth and William M. rowel-tn. Cleveland, Ohio Application July 26, 1932, Serial no. 624,774

15 Claims.

This invention relates. to fluid pressure actu-.

ated devices and more particularly to control mechanism for controlling the flow jof actuating fluid to and from such apparatus.

In our co-pending United States patent application, Serial No. 533,076, filed April 27, 1931, now

Patent No. 1,968,484, a division of our application,

Serial No. 483,328, filed September 20, 1930, we have described and claimed a control valve arrangement which is particularly adapted for use with fluid pressure actuated brake systems of the vacuum or sub-atmospheric pressure ype. The present invention relates to improvements in the general type 01' valve shown in our above noted cam-pending application. and contemplates the provision of a valve which will provide a control action particularly suited for vehicle brake operation. The present application is a continuation in part of our above noted co-pending application, Serial No. 533,076 new Patent No. 1,968,484.

A numberof valve devices have been, proposed for controlling the action of fluid pressure oper-,

ated brakes. One of the important requirements of such a device is thatitbe able to control the flow of actuating fluid to and from the operating cylinder in such a way that a smooth and accurately controlled application of the brakes may be obtained together with an instantaneous release of the braking force when desired.

In our co-pending application, Serial No. 561,-

569, flied September 8, 1931, we have described and claimed a brake actuating mechanism in which means are provided for taking up the lost motion and slack in the brake operating connections and placing the brake shoes substantially in contact with the brake drums upon the preliminary or initial movement of the control mecha- This mode of operation of fluid pressure actuated brakes possesses certain distinct advantagesinthatitcausesthebrakemechanismtobe almost instantaneously moved into a position where further movement will cause braking effect and eliminates any lag or slow application of the brakes while permitting an effective control oi the actual braking operation. Inthe usual typejof -vehicle brakes with which we are familiar, and

particularly those used on automobiles, a certain clearance is normally maintained between the brake drums and the brake shoes to prevent drag, and it is among the objects of our invention to provide a control mechanism for fluid pressure actuated brakes in which the slack in the brake connections and the clearance between the brake drums and brake shoes willbe rapidly taken up during the initial movement or the control apparatus and the parts maintained in clearance takeup position until it is desired to carryout the actual braking operation. i Other objects of our invention arezl the provision of control mechanism for thecylinder of a fluid pressure actuated device which willpermit a certain predetermined operating pressure to be established within thecylinderupon theinitial movement of the control mechanism the provision of control, echanism for fluid pressure actuated devices in which an indication is given to the operator when the apparatus has reached the point where the initial actuating pressure has been established within the cylinder; theprovision of a control valve of the type descrlbedin our first above noted co-pending United-States patent application which incorporates means for automatlcallyretarding the closing of thevalve after it has been given an initial operating movement until a pre-determined operating pressure has been established within the cylinder and then quickly closing the valve to maintain this pressure in the cylinder; the provision of an extremely simple and compact control valve construction for fluid pressure actuated devices which is automatic in some of its actions and requires a minimum amount of attention and adjustment.

The above and other objects of our'invention will appear from the following description of a preferred and modified form thereof reference being bad to the accompanying drawings, in which:-

Figure '1 is a side elevation of a fluid pressure actuated device including a cylinder and our improved control valve arrangement.

Figure 2 is a vertical longitudinal section of'the apparatus shown in Figure l, the piston and piston rod end of the cylinder being omitted and the valve parts being shownin their normal or of! position. 7 a

Figure 3,-is a crosssectional view of our valve construction taken on lines. 3-4 of Figure 2.". l j

Figure 4 is a fragmentary sectional view simi lar to Figure 2 but illustrating thevalve partsin the positions they assume upon completion of the initial movement thereonwhiclr movement,es-' tablishes. a ire-determined operating, pressure within the cylinder. I

Figure 5 is a fragmentary sectional view of an-Q v othertorm 01' our improved valve structure 'showing a modifled'nain diaphragm control disc.

' Figure 6 is an end elevation taken on line 6-6 of Figure 5 and illustrating one. shape which we have found suitable for the diaphragm-control disc lllustratedinl lgure 5.;

' Referring now to Figures 1 and 2, the cylinder I, which is adapted to carry the piston 2, is secured to the piston rod 3 which extends out through the end cap 4 of the cylinder. The piston rod 3 may be connected in any suitable manner to operate any desired apparatus, such as the brakes of an automotive vehicle. The end cap 4 is provided with an atmospheric connection conduit 5 which may extend to an air filter (not shown) and serves to maintain a permanent connection between the right hand end of the piston .2 and the atmosphere. The control valve mechanism is preferably enclosed within the housing 6 which may be formedintegrally with the end cap I. The housing 6, in the apparatus illustrated, is provided with a hole 8 through which a bolt or screw may be passed to mount the apparatus in any desired location.

The control valve operating lever 9 is keyed or otherwise secured to the transverse shaft l and is provided with a forked upper end A fin or rib l2, preferably formed integrally with the end cap I and valve housing 6, extends upwardly and is provided with a longitudinally extending aperture l3. A slot i4 extends through the side of the flange |2 into the aperture l3. An operating bar l5, preferably rectangular in cross section, has a sliding fit within one end' of the aperture |3 which is of corresponding rectangular section to the bar l5. At the end of the bar IS a pin fliextends outwardly through the slot l4 and passes through the prongs of the forked end ll of the valve operating lever 9. A transverse pin |1 may be provided in the end of the pin It to assist in holding the parts in their proper positions. The left hand end of the aperture I3 forms a housing for the spring |8 the position of which may be adjusted by the screw I9 or by other suitable adjustingmeans. The

adjusting screw |9 has threaded engagement inthe flange l2 and may be provided with a lock nut 20'fo r securing it in the desired position. The flanged head or contact plug 2| is supported in the right hand end of the spring l8 and is adapted to be engaged by the inner end of the rod l as will be more fully described later. .The outer or right hand end of the rod I5 is adapted to be connected to any desired operating means such as the rod 22. It will beunderstood that the rod 22 may be replaced by a cable or other connecting means and may extend through suitable connections to an operating point such as the control pedal of an automobile.

The shaft l0 extends transversely of the housing 6 and, as is clearly seen in Figures 2 and 4, carries a cam member 23 which is adapted to engage the face of the guiding piston or plunger 24. The chamber 25 which carries the plunger 24 is closed at its outer end by the end plug 26. However, the chamber is connected to the atmosphere through a suitable conduit 21 which may, if desired, also be connected to an air filter (not shown) to prevent the entry of harmful material to the apparatus. The plunger 24 is provided with holes 28 which permit air to pass freely therethrough and therefore permit the plunger to be freely moved within the chamber 25. A tube 29 is secured to the plunger 24 and is supported by the bearing 30. This tube 29 carries the valve closure member 3| at its inner end.

The end cap I is internally threaded at its open end and is screwed into position on the end of the cylinder A cup shaped member 32 is adapted to fit the bore of the endcap 1 and is held in position-between the end of the cylinder and the annular shoulder 33 of the cap I. The member 32, together with the end cap I, form a main diaphragm chamber 34 and an auxiliary or secondary diaphragm chamber 35 is formed on the cylinder side of the separating 5 wall member 32. The auxiliary chamber 35 is provided with a cap 36 which seats against the auxiliary diaphragm 31 at its outer periphery and holds it in' position. Communication between the interior of the cylinder and the diaphragm chamber 35 is established by a relatively small bleeder hole 38. A plunger 39 is secured at one end to the auxiliary diaphragm 31 and extends through the wall 32 into the main diaph agm chamber 34 where it is provided with an enlarged disc seat 40 which is adapted to co-act with the closure member 3|.

A second annular seat 4| is adapted to engage the opposite side of the closure member 3| and is secured to and supported by the main diaphragm 42. vThe seat 4| is provided with a tubular central neck 43 which surrounds the tube 29 and extends into the chamber 44 in the housing 6. Packing 45 may be provided to maintain a fluid tight joint between the tube 43 and the housing 6 through which it passes. The chamber 44 is connected to a source of supply of actuating fluid pressureby a conduit 46. Any desired source of actuating pressure may be utilized,

for example, the intake manifold suction of an 80 automotive vehicle.

The main diaphragm chamber, on the right hand side of the diaphragm 42, is connected to the interior of the cylinder by the passages 41 and, on the left hand side of the diaphragm 42, to the atmosphere through the passage 48 which extends into the chamber 25. 1

The control valve apparatus which has been described up to this point of this specification is substantially the same as to structure and modem of operation as that described and claimed in our above noted co-pending application, Serial No. 533,076, now Patent No. 1,968,484.

Inorder to secure the desired action of our fluid pressure actuated apparatus in which the initial movement of the operating lever 9 causes a. pre-determined pressure to be established within the .cylinder I we have provided the main diaphragm control disc 49. This disc, which is seen in end elevation in Figure 3, is secured at its outer 50 periphery by the clamping action between the end cap I and the member 32 and may be spaced from the main diaphragm 42 by a suitable washer. The control disc .49 in the preferred form of our apparatus, as shown in Figures 2 and 4, is not absolutely flat but is formed with annular grooves, substantially as shown, in order to give the desired snap-over action which will be later explained. A resistance disc 50 is spaced from the control disc 49 by a suitable washer and is held in position by the end cap 'I-in the same manner as diaphragm 42 and control disc 49. The control disc 49 and resistance disc 50 are formed with apertures at their centers which are large enough to permit the seat 4| and the closure member 3| to move freely therethrough.

When the bar I5 is moved to the left (Figure 1) the pin l6 causes the control lever 9 to move, turning the shaft l0 and the cam 23. This rotation of the shaft I9 causes the cam 23 to push against the plunger 24 moving it to the right (Figures 2 and 4) against the return spring 24'. This movement of the closure member 3| to the right causes it to engage the disc 49 and close off the atmospheric connection. It will also move 4 z the closure member 3| away from the seat 4| and thus communication will be established between the source of reduced actuating pressure and the diaphragm chamber 34 through the tube 43, the chamber 44, and the conduit 46.

As the left hand side of the main diaphragm 42 is connected to the atmosphere, it will be seen that, as soon as the closure member3| is movedaway from the seat 4|, and the pressure within the chamber 34 is reduced, the atmospheric pressureon the left hand side of the diaphragm 42 will tend to move this diaphragm ther with the seat 4| to the right. If this movement were not opposed it would result in the closing of the vacuum connection as soon as a pressure differ ential great enough to overcome the resiliency of the diaphragm 42 was built up.

It will be noted .that, in Figure 2, the portion of the control disc 49 adjacent its inner edge is in contact with the main diaphragm 42. Thus, when the pressure within the chamber 34 is reduced the control disc 49 tends to prevent movement of thediaphragm 42 to the right and thus maintains open the passage between the closure member 3| and the seat 4|. However, when a certain predetermined pressure differential exists between the chamber 34 and atmospheric pressure the at.- mospheric pressure will exert a force great enough to cause a snap-overaction of the disc 49 to take place. When this takes place the parts will assume the position shown in Figure 4 and the'seat 4| will again be in contact with the closure member 3| and the source of reduced pressure willbe shut off. The snap-over action above referred to is well understood and is similar to that which takes place when a disc of metal which is slightly dished or deformed snaps over from one side of its central plane to the opposite side. The discs 49 and 59 and the diaphragm 42 are preferably made of spring steel and by making them of the proper shape, gauge and temper the apparatus may be arranged so that the snap over action above described will take place when any predetermined pressure difierential has been reached between the diaphragm chamber 34 (and consequently the interior of the cylinder I) and the atmosphere.

As seen in Figure 4, after the snap-over action has taken place, the closure member is in contact phere and the source of vacuum. Thus, the predetermined vacuum conditions will be maintained within the cylinder until the lever .9 is given fur-, ther movement to the left causing the closure member 3| to again move toward the right.

When this movement takes place the diaphragm I will again be conthese members are overcome the vacuum conmotion will be closed and the valve structure as a whole will operate to give the desired smooth varl-.

ation in the working pressure within the cylinder.

. The release operation will be substantially the reverse of that above described and the snap-over action of the control disc 49 assist in the the cylinder.

-of the control and reduces the length of travel of clude the snap-over feature but which consists of return of the diaphragm 42 and the closure 4| to their normal position.

The auxiliary diaphragm 3] is adapted to retard the movement of the disc seat to the left when the control valve is moved .in closing direc-' 5 tion. An annularly corrugated disc spring 40 is seated at its outer peripheryon theseparating wall 32 and at its inner periphery engages the seat 40. This disc is preferably of spring steel or the like and tends to maintain the seat 40 in the position shown in Figure 2.

To understand the operation and function of the auxiliary diaphragm 31 let us assume that the closure member 3| has been moved to the right to establish a relatively high degree of vacuum with- 5 in the cylinder I. As the auxiliary diaphragmchamber 35 is connected to the cylinder I by the m I bleeder hole 38 the same low pressure conditions J will exist within the chamber 34 as exist within Now if the closure member 3| is moved to the leftit will move away from the. seat 40 and establish a connection between the chamber 34 and the atmosphere. The air under a.t

, mospheric pressure rushes in between the disc 49 and the closure member 3| and very quickly permits the pressure conditions within the cylinderl to approach atmospheric pressure. However, the small bleeder hole 38 retards the flow' of air into the chamber 35 and thus a certain suction will be exerted against the diaphragm 31 which tends to maintain it in its right hand position against the opposing force of the spring disc 49'. This retarding of the disc 40 by the diaphragm is only momentary as, as soon as the pressure in the cylinder and theauxiliary cham- 35 ber 35 are. equalized, the spring disc will force the seat 40 to the left into contact with the closure member 3|. However, this momentary retarding action on the seat 40 is suificient to permit an almost instantaneous reduction of theeffective pressure in the cylinder to a point corresponding to the position of closure member 3|. 1

The snap-over action of the control disc 49 is particularly advantageous as it creates a relatively high resistance to movement of the diaphragm 42 up to the point where the snap-over action has taken place. After the snap-over action has taken place, however, the disc 49 may be relatively freely flexed and does not offer. excessive re.- .with both of the seats 4| "and 49 and the interior of the cylinder is closed off both from the atmossistance to movement of the diaphragm42. In fact we have found that it is desirable to employ the resistance disc 50 to add to the resistance of the diaphragm 42 and the snap-over disc 49. This additional resistance increases the sensitivity the closure member 3| to securethe desired range of pressure control.

In Figures 5 and. 6. we have illustrated a modified form of resistance disc which does not ina disc 5| of spring steel or the like which is interposed between the: main diaphragm 42' and the resistance disc 50.

The disc 5| is formed with a central aperture 52 (Figure 6)- and radially extending slots 53. These slots form inwardly projecting tongues 54 which are bent out of the main plane of the disc as seen. in Figure 5. The disc 5| is preferably made of relatively light material. The action of our apparatus when equipped with a control device of this type is substantially the same as that above described in' reference to Figures 2 and 4. However, the snap-over action does not take I place, but, as the resistance disc 50 is made relau tively heavy, the initial movement oi. the closure pressure as soon as the-pressure 'difl'erential ,on ance to movement of said diaphragm until a s the opposite sides of the diaphragm 42 becomes mredetermined operating pressure is reached in great enough to flatten out the tongues it of the said cylinder and then to ofier a relatively small resistance disc 5|. Aiter this has taken place resistance to further movement of said diafurther movemnt'o'i the diaphragm 42 will be phragm; I against the relatively great-resistance oi the con- 4. In a valve for controlling the flow of ac- 1o trol disc 5| plus that of the resistance disc 50. 'tuating fluid to a cylinder, a movable, closure In adapting our control mechanism to fluid member, a movable seat therefor, means for movpressure operated brakes or the like we prefer ing said closure member away from said seat, to adjust the positionoi the spring it so that the means, including a fluid. pressure actuated dialeit hand end of the bar i5 will contact with the phragm, for moving said seat toward said 010- the diaphragm takes place.

member.

, in one position to connect the' cylinder to over disc, for retarding the closing of thesubfluid to and from a cylinder including a housing diil'erential between the opposite sides of said diaphragm, and means, eflective upon 'the initial opening of the valve and independent 01' said diaphragm for imposing a relatively great resistmember will'causeit to move away irom the seat M, which seat ll will be again moved into con,- tact with the closure member by atmospheric sure member, and a snap-over disc adapted to moved into the position shown in Figure 4. The retard movementoi said diaphragm until a preeffect or this adjustment is that, whenthe operdetermined pressure differential is established ator moves the bar i5, its initial movement willbetween the opposite sides of said diaphragm.

be against very little resistance. This initial v movement will open the suction connection and tuating flu idto a cylinder, a movable closure permit the pressure within the cylinder to be member, a movable seat therefor, means for reduced to a point when" the snap-over'action of moving said closure member away from said seat.

' II, for example, the means, including a, diaphragm, for moving said piston rod the connected to a brake system the seat toward said closure member and means for 9,5

degree of .vacuum preliminarily established in imposing an added resistance to the initial movethe cylinder by this action will preferably be just ment of a said diaphragm and seat towards said enough to exert suflicient force to maintain the closure member until a predetermined pressure brakes in clearance take-up position as above differential is established between the opposite described. The operator can feel when he reaches sides of said diaphragm and then releasing said to this point in the movement of the bar I! as additional resistance. iurther movement of thebar I! will be against 6. Ida valve of the type described, a diathe resistance 0! the spring 18. The operator,

phragm', a seat member carried, by and movable therefore-during the first relatively short movewith said diaphragm, and means for retarding head 2| when the closure'member 3| has been ment of the operating lever places the brakes in movement oi said diaphragm and seat member 15 P n f r immediate pplication. This actionin one direction .until a predeterminedpressure takes place very quickly and we have found it to dlflerential is established between the opposite be of distinct advantage in fluid pressure oper-. sldesmt said diaphragm and then permitting related devices, particularly those which are used atively free movement of said diaphragm. for applying the brakes of an automotive vehicle.

Although. we have described in considerable hr g'm, a seat member carried by and movable detail the forms ofour invention illustrated in with said diaphragm and a snap-over: disc the attached drawings it will be understood that adapted to engage said diaphragm and retard mediflcatiolls and fl' t l h f may be movement'thereoi until a predetermined presmade without departing fr m-the Spirit f 111' sure diflerential is established between the on 4,5 invention. we do not, therefore, limitourselves osite sid s of said diaphragm,' v I td the specific details shown and described, but Y8, In a valveli'or controlling the flow oi actuatclaim as our invention all embodiments thereof ing fluid to and from a cylinder, a housing coming within the scope of the appended claims. adapted to form a diaphragm chamber. a diemwwe claim:- phragin in said'chamber, said diaphragm haviha 50 1. In a control valve mechanism or the type a seat portion, a closure member adapted nordescribed: a movable closure member, a movable mally to seat on said diaphragm seat portion, Q

seat adapted to be movedby fluid pressure to means for'lnoving said closure member. away engage said closure member, means for separat- .n-om said diaphragm seat portion, and a snaping said seat and closure member and means, over memberadapted to resist movement 01 said '55 including a snap-over disc, for retarding initial diaphragm after said closure member isinitiaiiy movement of said seat toward said -closure. moved' away therefrom until a predetermined fluid pressure d iflerential is built up between the oppositesides of said diaphragm.

9. A valve of the class described in maintain a definite operating-pressure in a cylen inder tor each position'ot the valve including,'a a" movable seat, means, including a resilientnd iasource oi sub-atmospheric fluid pressure and phragm; responsive to the operating pressure in when in another position to connect thecylinder the cylinder, for positioning said seat,"and means as to the atmosphere, and means, including a snapior- 'retardingthe" initial movement of said seat until a predetermined operating pressure is esatmospheric connection during the initial open tablished in the cylinder and then permitting rel- 2. A valve for controlling the flow of actuatin having a diaphragm chamber, a diaphragm said chamber, a closure member adapted wh ing movement of the closure member. atively'iree movement of said diaphragm.

3. In a'valveior controlling the flow of 2.0- 10. A valve oi -the class described adapted, to

- tuatingfluid to a cylinder, a closure membenja maintain a definite operating pressure in a cylseat'tor said closure member, means ior moving said closure. member away from saidseat, dia: phragm means for seating said closure member inder for each position-oi the-valve including,,a movable'seauhmeans, responsiveto' the oper ating-pressure' in thecylinder, ior'positioning and seat upon the establishment or a-pressure and seat, and a snapover member adapted to! 5.-In a valve for controlling the-flow or ac-go 7.-In a valve of the type described, :1 dia- 11 adapted to so impose a relatively great resistance to movement of said seat in closing direction until predetermined pressure conditions are established within the cylinder and then to snap over and offer a relatively slight resistance to further movement of said seat in closing direction.

11. A valve of the class described adapted to maintain a definite operating pressure in a cylinderfor each position of the valve including, a movable seat, means, responsive to the operating pressure in the cylinder, for positioning said seat, a snap-over member adapted to impose a relatively great resistance to movement of said seat in closing;direction until predetermined pressure conditions are established within the cylinder and then to snap over and offer a relatively slight resistance to further movement of said seat in. closing direction and means,..eifective after said snap over action has taken place, for offering additional resistance to movement of said seat.

12. In apparatus of the class described, a cylinder and a valve for controlling the flow of actuating fluid to the cylinder, said valve including a closure member having oppositely disposed seating surfaces, movable seats adapted to engage the seating surfaces of said closure member, means for moving one seating. surface of "said closure member out of seating engagement with one of said seats while maintaining the other seating surface in engagement with the other of said seats, means for preventing movement of said first mentioned seat toward said closure member until a predetermined pressure is established within said cylinder and means for retarding movement of said second named seat when said closure member is moved in the opposite direction whereby the closure member will be unseated from said second seat.

13. In a valve for controlling the flow of actuating fluid to a cylinder, a closure member hav tion whereby the closure member will be unseated from said second seat.

14"? In a vaive of tiitype described, a 'closure member,'a diaphragm, a movable seat supported on and movable with said diaphragm, and a snapover member adapted to engage said diaphragm and to resist movement thereof toward said closure member. r

15. In a control valve for fluid pressure actuated apparatus, a closure member, a movable seat and means, including a snap-over disc, for ofiering relatively great resistance to movement of said seat upon the initial movement of said closure member away from said seat and adapted to snap over and offer relatively slight resistance to move- -ment of said seat upon establishment of predetermined fluid pressure conditions within the fluid pressure actuated apparatus.

FREDERICK G. FOLBERTH. WILLIAM M. FOLBERTH. 

